A genetically closed population of Japanese Black cattle consisting of a line originated from ancient “Tsuru-ushi” has been bred in Okayama prefecture by avoiding intercross with other lines. For the purpose of conservation of this rare line, we performed genetic characterization of this line by using microsatellite markers. Genotyping of 23 microsatellite markers in 39 animals of the rare line and 33 animals of other populations as controls revealed that average number of alleles, effective number of alleles, average observed heterozygosity, and average expected heterozygosity are 3.22, 2.04, and 0.4827, 0.4599, respectively, and these values were lower than those of the control animals. Inbreeding coefficient, average number of alleles, and average heterozygosity of the animals of different generations revealed increased inbreeding coefficient and decreased average heterozygosity during progression of generations, indicating decreasing genetic diversity in the rare population. Bayesian clustering and phylogenetic analyses using the marker genotypes were performed to examine the genetic relationship among the 72 animals. The result of the clustering analysis and phy ogenetic tree revealed that the animals in the population of the rare line were clearly distinguished from those of the control population and that these animals were further divided into two groups which are essentially correspond to the pedigrees of the line. These findings will be valuable for conservation of this rare line and for the use of this line to the breeding of Japanese Black cattle.
Mishima cattle is a rare breed originated from Japanese native cattle and has been registered as national natural treasure of Japan. Various polymorphisms of genes associated with economical traits such as growth rate, beef marbling and fatty acid composition, and mutant alleles of genes responsible for hereditary diseases have been identified in Japanese Black cattle, but no data regarding these polymorphism and mutant alleles in Mishima cattle has been reported. Therefore, we investigated whether these polymorphisms and mutant alleles are existing in Mishima cattle in this study. We genotyped F11 , LYST and CL16 genes responsible for factor XI deficiency, Chediak-Higashi syndrome, and renal tubular dysplasia, respectively, MC1R gene involved in coat color, EDG1 , SCD and SREBP1 genes associated with beef marbling and fatty acid composition, and POU1F1 and GHR genes associated with growth rate in DNA samples of ten Japanese Black cattle and eleven Mishima cattle. Consequently, no mutant alleles of F11 , LYST and CL16 loci, E + allele of MC1R locus, and G allele of EDG1 locus was observed in the samples of the Mishma cattle examined. On the other hand, two alleles were observed in SCD , SREBP1 , POU1F1 and GHR loci in the samples of the Mishima cattle as in the case of the Japanese Black cattle, although there frequencies were different between these two breeds. These findings will be informative for investigating the genetic characteristics of the Mishma cattle.